JP2004080193A - Ultrasonic transducer and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fine high performance ultrasonic transducer with less deterioration in the piezoelectric and dielectric characteristics. <P>SOLUTION: The ultrasonic transducer includes: a packing material (14); a plurality of layered piezoelectric materials (11) placed thereon in a form of an array; and a plurality of acoustic matching layers (12, 13) placed on the respective layered piezoelectric materials. Each of the layered piezoelectric bodies (11) is provided with: a laminate including first and second piezoelectric materials that are alternately layered and completely subjected to polarization processing in opposite directions to each other; first and second external electrodes placed to side faces of the laminate opposite to each other, respectively; a first internal electrode placed in direct contact with the upper face of the first piezoelectric material and the lower face of the second piezoelectric material, electrically connected to the first external electrode, and in contact with the second external electrode via a U-shaped insulation part; and a second internal electrode placed in direct contact with the upper face of the second piezoelectric material and the lower face of the first piezoelectric material, electrically connected to the second external electrode, and in contact with the first external electrode via the U-shaped insulation part. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ultrasonic transducer mainly used for a medical ultrasonic diagnostic apparatus and a nondestructive inspection apparatus, and more particularly to an ultrasonic transducer using a laminated piezoelectric body and a method of manufacturing the same.
[0002]
[Prior art]
In the field of medical ultrasonic diagnostic equipment and nondestructive testing equipment, PZT (lead zircon-titanate) piezoelectric ceramics and relaxor / lead titanate piezoelectric single crystals are used as ultrasonic transducers for transmitting and receiving ultrasonic waves. ing.
[0003]
Conventionally, a one-dimensional array probe in which a plurality of strip-shaped PZT piezoelectric ceramic vibrators are arranged is mainly used as an ultrasonic transducer of a medical ultrasonic diagnostic apparatus. Recently, an ultrasonic transducer using a laminated piezoelectric material has been developed to increase the sensitivity of the one-dimensional array probe or to enable low-voltage driving.
[0004]
In addition, from the demand for a conventional two-dimensional (tomographic) image to a three-dimensional image, a two-dimensional array probe in which minute rod-shaped vibrators are two-dimensionally arranged has been studied. In a two-dimensional array probe, since one element is very small, when conventional piezoelectric ceramics is used, the impedance increases and the transmission / reception sensitivity decreases. For this reason, a two-dimensional array probe using a laminated piezoelectric body has been studied.
[0005]
The laminated piezoelectric body has a structure in which a plurality of piezoelectric bodies and internal electrodes are alternately laminated. PZT ceramics is used as the piezoelectric body, and Pt and Ag / Pd are used as the internal electrodes, and simultaneously fired (1100 to 1250 ° C.). Can be configured. These techniques are described in US Pat. L. Goldberg, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, vol. 41, no. 5 September 1994, pp. 139-143. 761 to 771. For the internal electrodes in such a laminated piezoelectric body, for example, every other layer of the internal electrode is coated with an insulating material such as glass, and the internal electrode ends that are exposed every other layer are commonly connected with a conductive material. As a result, conduction is achieved. Although it is necessary to perform the polarization treatment of the piezoelectric body after connecting the wiring of the internal electrode, it becomes structurally difficult to apply an ideal electric field as the vibrator becomes finer. As a result, sufficient polarization processing cannot be performed. Further, the mechanical load generated by the material connecting the wiring of the internal electrode on the side surface of the vibrator also increases, and it becomes difficult to sufficiently bring out the inherent characteristics of the piezoelectric body. In fact, the vibrator manufactured by co-firing has a tendency that the electromechanical coupling coefficient decreases while the effective capacity increases.
[0006]
On the other hand, since the laminated piezoelectric body co-fired is expensive and difficult to manufacture, a piezoelectric plate having a plurality of gap grooves is laminated in advance with an adhesive, and then divided by dicing and subjected to ultrasonic probe. A method of manufacturing a child has been proposed (JP-A-2001-29346). However, in this method, the alignment of the gap grooves in the upper and lower layers cannot be easily performed. In addition, there is a problem that the mechanical strength is insufficient due to the adhesive laminate, and it is difficult to divide by dicing.
[0007]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide a fine high-performance ultrasonic transducer having a sufficient mechanical strength with little reduction in piezoelectric and dielectric properties such as an electromechanical coupling coefficient.
[0008]
In addition, the present invention makes it possible to easily manufacture a fine high-performance ultrasonic transducer having sufficient mechanical strength with a small decrease in piezoelectric and dielectric properties such as an electromechanical coupling coefficient by using a co-fired laminated piezoelectric body. It is intended to provide a method for doing so.
[0009]
[Means for Solving the Problems]
According to one aspect of the present invention, a backing material, a plurality of laminated piezoelectric bodies arranged in an array on the backing material, and a plurality of acoustic matching layers disposed on each of the laminated piezoelectric bodies are provided. Have
The laminated piezoelectric body,
A stacked body including first and second piezoelectric bodies that are alternately stacked and completely polarized in opposite directions to each other;
First and second external electrodes respectively disposed on opposing first and second side surfaces of the laminate,
The upper surface of the first piezoelectric body and the lower surface of the second piezoelectric body laminated on the first piezoelectric body are arranged in direct contact with each other, and are electrically connected to the first external electrode. A first internal electrode in contact with the second external electrode via a U-shaped insulating portion;
The upper surface of the second piezoelectric body and the lower surface of the first piezoelectric body laminated on the second piezoelectric body are disposed in direct contact with each other, and are electrically connected to the second external electrode. , And a second internal electrode which is in contact with the first external electrode via a U-shaped insulating portion.
[0010]
According to another aspect of the present invention, a plurality of piezoelectric bodies and internal electrodes are alternately stacked and simultaneously fired, and each piezoelectric body is subjected to a polarization treatment and cut into a predetermined shape. While maintaining the temperature below, a U-shaped insulating portion is formed at one end of the internal electrode, and an external electrode connected to the exposed end of the internal electrode is formed. The step of obtaining
An ultrasonic wave comprising: a step of arranging a plurality of the laminated piezoelectric bodies in an array on a backing material; and a step of arranging an acoustic matching layer on each of the laminated piezoelectric bodies arranged in the array. A method for manufacturing a transducer is provided.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an example of a structure of a laminated piezoelectric material used in an ultrasonic transducer according to an embodiment of the present invention.
[0012]
The laminated piezoelectric body shown in FIG. 1 has a plurality of piezoelectric bodies 1a and 1b laminated via only the internal electrodes 2a and 2b, and covers the respective ends of the internal electrodes 2a and 2b alternately on one side surface. And external electrodes 3a and 3b electrically connected to the ends of the internal electrodes 2a and 2b exposed on the other side surface, respectively. Piezoelectric 1a, as is 1b, piezoelectric ceramic or _{PZNT (Pb (Zn 1/3 Nb 2/3} ) O 3 -PbTiO 3) , such as PZT, barium titanate or PMNT _{(Pb (Mg} 1/3 _{Nb 2/3} ) A piezoelectric single crystal such as O ₃ —PbTiO ₃ ) is used, and is completely polarized in the direction indicated by the arrow in the figure. Two types of piezoelectric bodies that are alternately stacked and polarized in the opposite direction can be referred to as first and second piezoelectric bodies. Specifically, the first piezoelectric member 1a and the second piezoelectric member 1b disposed thereon are joined only via the first internal electrode 2a. The first internal electrode 2a is electrically connected to the first external electrode 3a, and is in contact with the second external electrode 3b via the insulating material 4. Further, the second piezoelectric member 1b and the first piezoelectric member 1a disposed thereon are joined only via the second internal electrode 2b. The second internal electrode 2b is electrically connected to the second external electrode 3b, and is in contact with the first external electrode 3a via the insulating material 4.
[0013]
Pt, Ag / Pd or the like can be used as the internal electrodes 2a and 2b, and an Au / Cr sputtered film or the like is used as the external electrodes 3a and 3b. Further, as the insulating material 4, a material that cures at a temperature equal to or lower than the Curie temperature of the piezoelectric body 1, for example, an epoxy resin is used.
[0014]
The laminated piezoelectric material used in the embodiment of the present invention can be manufactured, for example, by the following method. First, the piezoelectric bodies 1 and the internal electrodes 2 are alternately laminated, and a laminated piezoelectric body is manufactured by simultaneous firing. The thickness of one layer of the piezoelectric body 1 is about 10 to 300 μm, the thickness of the internal electrode 2 is about 0.5 to 10 μm, and about 2 to 10 layers are laminated. At this time, in order to remove the unpolarized portion or the non-uniformly polarized portion by processing after the polarization, it is desired that the width and the length of the laminated piezoelectric material be sufficiently large. For example, when obtaining a plate-shaped vibrator having an area of 12 mm × 24 mm, the width and the length are about 22 mm and 34 mm or more, respectively. After the lamination, the internal electrodes 2 are temporarily connected every other layer, and a polarization process is performed on the piezoelectric body 1 by applying an electric field of 1 to 3 kV / mm for several minutes. Then, it cuts into the shape used as an ultrasonic transducer, for example, the plate shape whose area is about 12x24 mm. After the polarization process, the wafer is cut into a predetermined shape, so that after the cutting, all the piezoelectric layers are completely polarized up to the ends, that is, a state in which the polarization directions are uniform in all the planes. .
[0015]
Next, a concave groove is formed on each side of the laminated dielectric using a dicing saw or the like so as to remove the end of the internal electrode 2 exposed on one side of the laminated piezoelectric. . It is preferable that the groove depth (the horizontal direction in FIG. 1) is about 10 to 100 μm. When the thickness is less than 10 μm, it is difficult to sufficiently insulate. On the other hand, when the thickness exceeds 100 μm, a portion where a voltage cannot be applied becomes an ineffective portion that cannot be ignored, and the piezoelectric characteristics may be deteriorated. In particular, it is preferable that the depth of the groove is determined so as to satisfy the condition represented by the following equation (1), since there is almost no decrease in piezoelectric characteristics and the characteristics of the ultrasonic transducer are improved.
[0016]
_{w 2 / w 1 ≦ 0.15 (} 1)
(Here, w ₁ is the width of the piezoelectric body, w ₂ is the depth of the groove.)
Further, the width of the groove (vertical direction in FIG. 1) is preferably about 10 to 30 μm. When the thickness is less than 10 μm, it is difficult to sufficiently insulate. On the other hand, when the thickness is more than 30 μm, the effect of a mechanical load due to the insulating material to be filled appears, and the piezoelectric characteristics may be deteriorated. In particular, it is preferable to determine the width of the groove so as to satisfy the condition represented by the following equation (1), since the performance of the ultrasonic transducer is improved with almost no deterioration in piezoelectric characteristics.
[0017]
_{t 2 / t 1 ≦ 0.5 (} 2)
(Here, t ₁ is the thickness of the piezoelectric body, and t ₂ is (groove width) / 2.)
The grooved side surface is immersed in an etching solution such as ammonium fluoride or nitric acid. By this etching process, the concave groove is isotropically etched, so that a corner is removed and a U-shaped shape is obtained. The most preferred shape is a semicircle, since the cross-sectional area is small and no stress is concentrated. Similarly, U-shaped grooves are formed on opposing side surfaces so that the grooves on both side surfaces are alternated as shown in the drawing. Since the grooves formed on the side surfaces of the laminated piezoelectric body are U-shaped and have no corners, there is no risk of crack breakage from the corners, which is advantageous in terms of mechanical strength. Moreover, since the cross-sectional area of the groove is smaller than that of the case of the concave square groove, the mechanical load is small and the piezoelectric characteristics are improved.
[0018]
The U-shaped groove formed in this manner is filled with an insulating material 4 such as an epoxy resin, which is applied and cured or deposited and deposited by sputtering. A typical epoxy resin has a value of acoustic impedance of about 3.2 Mrayls, but as this value is smaller, characteristics such as an electrical coupling coefficient are improved. For example, the acoustic impedance of a special epoxy resin such as EPO-TEK301 (manufactured by epoxy technology) is about 3 Mrayls, and the acoustic impedance of liquid or air is about 2 Mrayls. Therefore, it is most preferable that the U-shaped insulating portion is formed of a groove and an insulating material such as liquid or air filled therein.
[0019]
Since the polarization process is performed on the piezoelectric layer in the preceding step, the subsequent processes such as application and curing of the insulating material must be performed at a temperature lower than the Curie temperature of the piezoelectric material. The Curie temperature is determined according to the type of the piezoelectric body. For example, it is about 200 to 300 ° C. for PZT piezoelectric ceramics and about 175 ° C. for PZNT piezoelectric single crystal.
[0020]
After the formation of the U-shaped insulating portion, electrode films to be the external electrodes 3a and 3b are formed on both side surfaces by sputtering. The external electrodes 3a and 3b are also formed at a temperature equal to or lower than the Curie temperature of the piezoelectric body as described above.
[0021]
According to the above-described method, ten layers of the piezoelectric body 1 having an area of 12 × 24 mm and a thickness of 60 μm were laminated via the internal electrode 2 and processed into a 0.200 mm-wide strip-shaped vibrator, as shown in FIG. Such a laminated piezoelectric body was obtained. Measurement of the electromechanical coupling coefficient of the multilayer piezoelectric body, about 66% in the value of the electromechanical coupling factor k _'33 was obtained. This value is almost the same as the value of 69% of the bulk piezoelectric material not laminated. Therefore, it was confirmed that the use of the embodiment of the present invention hardly caused a deterioration in characteristics due to lamination. The graph of FIG. 2 shows the impedance characteristics of the laminated piezoelectric vibrator obtained here. In the graph of FIG. 2, the size of the arrow corresponds to the size of the coupling coefficient.
[0022]
For comparison, FIG. 3 shows the impedance characteristics of a multilayer piezoelectric body prototyped using the conventional technique. Specifically, a laminated piezoelectric body was manufactured by employing the method described in JP-A-2001-102647. In the laminated piezoelectric body thus manufactured, the portion of the insulating material is concave, and its cross section is larger than that in the case of the U-shape. In addition, the polarization treatment is performed after laminating a plurality of piezoelectric layers, since an adhesive curing process at 200 ° C. or higher is included. For this reason, an ineffective portion is generated at the end of the piezoelectric layer, and in some cases, unnecessary vibration is generated as shown in the graph of FIG. 3, and the electromechanical coupling coefficient may be reduced.
[0023]
As shown in the graph of FIG. 2, the laminated piezoelectric vibrator manufactured by the above-described method has no unnecessary vibration, and the electromechanical coupling coefficient maintains the characteristics of the bulk piezoelectric body without lamination. In such a laminated piezoelectric body, the piezoelectric layers are laminated via only the internal electrodes and are manufactured by simultaneous firing, so that there is no adhesive. Therefore, a decrease in mechanical strength due to the adhesive is avoided. In addition, since the laminate is cut into a desired shape after being manufactured, the stack can be manufactured without a complicated process of performing positioning using a groove provided in the piezoelectric body. Moreover, since the apparent dielectric constant increases by the number of times of lamination, the ultrasonic transducer according to the embodiment of the present invention using this laminated piezoelectric body can be expected to greatly improve the characteristics such as the sensitivity.
[0024]
FIG. 4 is a schematic diagram illustrating a configuration of an ultrasonic transducer according to one embodiment of the present invention. The illustrated ultrasonic transducer is a one-dimensional array probe in which a plurality of laminated piezoelectric bodies 11 in which a first acoustic matching layer 12 and a second acoustic matching layer 13 are sequentially laminated are arranged one-dimensionally on a backing material 14. It is. Although not explicitly shown in FIG. 4, the laminated piezoelectric body 11 has a structure laminated in the same direction as in FIG. 1, and is manufactured by the above-described method. Such a one-dimensional array probe can be manufactured, for example, by the following method. First, the above-mentioned laminated piezoelectric body 11 is bonded to the backing material 14, and then the acoustic matching layers 12, 13 are formed. Finally, array processing is performed in a direction perpendicular to the side surface on which the external electrodes (not shown) are formed, and signal lines (not shown) are wired to the external electrodes on one side surface of each array, and the other side surface is formed. Are commonly connected to a GND line (not shown).
[0025]
In the ultrasonic transducer according to the present embodiment, the apparent dielectric constant of each transducer is improved, and the electromechanical coupling coefficient can maintain the characteristics of the bulk piezoelectric body that is not laminated. Therefore, it is possible to greatly improve the sensitivity and reduce the driving voltage.
[0026]
FIG. 5 is a schematic diagram illustrating a configuration of an ultrasonic transducer according to another embodiment of the present invention. The illustrated ultrasonic transducer is a two-dimensional array probe in which a plurality of laminated piezoelectric members 11 in which a first acoustic matching layer 12 and a second acoustic matching layer 13 are sequentially laminated are two-dimensionally arranged on a backing material 14. It is. Such a two-dimensional array probe is basically the same as the primary probe described above except that one row is prepared and array processing is performed, and signal lines and GND lines are connected, and then a plurality of transducer groups for this one row are joined. It can be manufactured by the same method as the original array probe.
[0027]
FIG. 6 shows an example of a method for manufacturing the two-dimensional array probe shown in FIG.
[0028]
First, as shown in FIG. 6A, one row of laminated piezoelectric bodies 11 is bonded to a flexible printed circuit board (FPC) 15 having a predetermined wiring pattern. The laminated piezoelectric body 11 can have, for example, the structure shown in FIG. Next, the ground-side electrode 16 and the signal-side electrode 17 of the FPC 15 and the electrode of the laminated piezoelectric body 11 are connected as shown in FIG. 6B using a thin-film electrode 18 such as an Au sputtered film. Further, as shown in FIG. 6C, the acoustic matching layers 12 and 13 are formed in the direction of transmitting and receiving ultrasonic waves, and the array is divided as shown in FIG. 6D. Finally, a filling resin is filled between the divided elements as shown in FIG. 6E, and the backing material 14 is bonded.
[0029]
By the above process, one row of the two-dimensional array probe is manufactured. A two-dimensional array probe is obtained by stacking and joining a plurality of transducers in one row as shown in FIG. 6 (f).
[0030]
FIG. 7 is a cross-sectional view showing the structure of another example of the laminated piezoelectric material used for the ultrasonic transducer according to the embodiment of the present invention.
[0031]
The illustrated laminated piezoelectric body has basically the same configuration as that shown in FIG. 1 and can be manufactured by the same process as described above. However, as the insulating material 4, a resin such as an epoxy resin having a low adhesive strength with the piezoelectric body 1 is used. By using such a resin, a gap as shown is formed between the concave groove on the side surface of the piezoelectric body 1 and the insulating material 4. Even when no gap is formed, a state in which the piezoelectric body 1 and the insulating material 4 are mechanically loosely bonded can be obtained. With such a structure, the mechanical load applied to the side surface of the piezoelectric body 1 is reduced, so that a decrease in piezoelectric and dielectric characteristics such as an electromechanical coupling coefficient can be reduced.
[0032]
An epoxy resin was formed as the insulating material 4 by sputtering, and a laminated piezoelectric body as shown in FIG. 7 having a partial gap between the concave groove and the insulating material (epoxy resin) was prototyped. The results obtained were evaluated laminated piezoelectric material is about 67% the value of the electromechanical coupling factor k _'33, as compared with the case where the bonding strength between the piezoelectric body with high epoxy adhesive, better properties was gotten.
[0033]
Further, the laminated piezoelectric material used in the ultrasonic transducer according to the embodiment of the present invention may have a sectional structure as shown in FIG.
[0034]
In the laminated piezoelectric body shown in FIG. 8, the inside of the U-shaped concave groove 5 is entirely void. This gap can be formed by the following method after forming a U-shaped groove by the same process as described with reference to FIG. The U-shaped groove is filled with a material that can be removed by etching, such as a resist material, and is cured. The material filled here is dissolved and removed using an etchant after forming external electrodes on both side surfaces. Alternatively, even if a material that is dissolved by heat or the like such as wax is filled in the U-shaped groove, the gap can be formed by a similar process.
[0035]
As already described, since the acoustic impedance of air is 2 Mrayls or less, by making the inside of the U-shaped groove hollow, it is possible to significantly improve the piezoelectric characteristics such as the mechanical coupling coefficient. This is because the inner surface of the groove does not receive any mechanical load due to the cavity.
[0036]
As a result of trial production and evaluation of a laminated piezoelectric material having such a structure, an electromechanical coupling coefficient almost equivalent to that of a bulk piezoelectric material was obtained.
[0037]
【The invention's effect】
As described above in detail, according to one embodiment of the present invention, there is provided a fine high-performance ultrasonic transducer which has a small decrease in piezoelectric and dielectric properties such as an electromechanical coupling coefficient and has sufficient mechanical strength. Further, according to another aspect of the present invention, a laminated high-performance piezoelectric transducer that has a small reduction in piezoelectric and dielectric properties such as an electromechanical coupling coefficient and has sufficient mechanical strength is co-fired. A method for easy production using a body is provided.
[0038]
INDUSTRIAL APPLICABILITY The present invention can be suitably used for a medical ultrasonic diagnostic apparatus, a nondestructive inspection apparatus, and the like, and its industrial value is great.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a structure of a laminated piezoelectric body in an ultrasonic transducer according to an embodiment of the present invention.
FIG. 2 is an impedance characteristic diagram of a laminated piezoelectric body in the ultrasonic transducer according to the embodiment of the present invention.
FIG. 3 is an impedance characteristic diagram of a conventional laminated piezoelectric body.
FIG. 4 is a schematic diagram illustrating a configuration of a one-dimensional array ultrasonic transducer according to an embodiment of the present invention.
FIG. 5 is a schematic diagram showing a configuration of a two-dimensional array ultrasonic transducer according to another embodiment of the present invention.
FIG. 6 is a process chart illustrating a manufacturing process of the two-dimensional array ultrasonic transducer according to the embodiment of the present invention.
FIG. 7 is a sectional view showing a structure of a laminated piezoelectric body in the ultrasonic transducer according to the embodiment of the present invention.
FIG. 8 is a cross-sectional view illustrating a structure of a laminated piezoelectric body in the ultrasonic transducer according to the embodiment of the present invention.
[Explanation of symbols]
1a, 1b: piezoelectric bodies 2a, 2b: internal electrodes 3a, 3b: conductive film (external electrode)
DESCRIPTION OF SYMBOLS 4 ... Insulator 5 ... U-shaped groove 11 ... Laminated piezoelectric body 12 ... 1st acoustic matching layer 13 ... 2nd acoustic matching layer 14 ... Backing material 15 ... Flexible printed circuit board 16 ... Ground side electrode 17 ... Signal line side electrode 18 ... Thin film electrode

Claims (5)

A backing material, comprising a plurality of laminated piezoelectric bodies arranged in an array on the backing material, and a plurality of acoustic matching layers disposed on each of the laminated piezoelectric bodies,
The laminated piezoelectric body,
A stacked body including first and second piezoelectric bodies that are alternately stacked and completely polarized in opposite directions to each other;
First and second external electrodes respectively disposed on opposing first and second side surfaces of the laminate,
The upper surface of the first piezoelectric body and the lower surface of the second piezoelectric body laminated on the first piezoelectric body are arranged in direct contact with each other, and are electrically connected to the first external electrode. A first internal electrode in contact with the second external electrode via a U-shaped insulating portion;
The upper surface of the second piezoelectric body and the lower surface of the first piezoelectric body laminated on the second piezoelectric body are disposed in direct contact with each other, and are electrically connected to the second external electrode. And a second internal electrode which is in contact with the first external electrode via a U-shaped insulating portion. 2. The ultrasonic transducer according to claim 1, wherein the U-shaped insulating portion comprises a concave groove provided over the adjacent first and second piezoelectric bodies. 3. The ultrasonic transducer according to claim 1, wherein the U-shaped insulating portion includes an insulating material having an acoustic impedance value of 3 Mrayls or less. The U-shaped insulating portion includes a concave groove provided over the adjacent first and second piezoelectric bodies, and an insulating material disposed in the concave groove without being mechanically coupled to the piezoelectric bodies. The ultrasonic transducer according to claim 1, comprising: A plurality of piezoelectric bodies and internal electrodes are alternately laminated and fired simultaneously, and each of the piezoelectric bodies is subjected to a polarization treatment and cut into a predetermined shape. Forming a U-shaped insulating portion at every other end of the electrode, forming an external electrode connected to the exposed end of the internal electrode to obtain a laminated piezoelectric body,
An ultrasonic wave comprising: a step of arranging a plurality of the laminated piezoelectric bodies in an array on a backing material; and a step of arranging an acoustic matching layer on each of the laminated piezoelectric bodies arranged in the array. Manufacturing method of transducer.

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